How to know when to replace leopard clutch drum?

Rod Hawkins · Joined: 23 Dec 2012 Posts: 11

This is my first post, hopefully not too dumb of a question. I did a search first.

Recently bought a kart with a Leopard engine. Chain just fell off of sprockets and the track operator made a comment that the sprockets look to be pretty warn out (which they are) and that the drum looks like it should be replaced. He just spin it without the Chain on to give me that info. He also sells stuff in the shop, so I am wondering if there is an easy way to tell if the drum is needing a replacement or not?

Russell Stevens · Joined: 15 Oct 2012 Posts: 100

Do you have the leopard manual, and/or the service manual? Did he say that the bushing or bearing was bad on the drum? He would have no way of telling if the contact surface of the drum was worn or damaged without pulling it off. Iame has wear limits on the clutch friction material, but the drum itself is a replace if damaged item. Pull the drum, replace the drive sprocket, and check the friction material and condition of the drum while you are in there.
Here is a link for a place to download the manuals. Have fun and don't be scared to crack it open and take a look. If you have questions, you can post pictures of the parts when you have the drum off and the folks here can help.
http://www.remoracing.com.au/products/engines/iameparillaleopardrl
Rusty

Clark Gaynor · Posted: Sun Dec 30, 2012 6:50 am Post subject:

You'll need a couple special tools for clutch work (pullers, piston stops, etc). Make sure you know which model Leopard you have before you order those tools. It will be either a MY07 (older) or MY09 (newer) model.

On either model you should get used to pulling the clutch drum and greasing the bearing(inside the drum) and cleaning both the drum and friction shoes. It's just part of normal service. We road race Leopards, and do clutch service at the end of each days running.

Oh ya', they do wear out engine, axle gears and chains pretty quickly. That's just part of the deal!

Russell Karting or Komet Kart Sales are both great for parts and info.

The manual Russell (not the shop) suggested is a very good idea. You'll learn a good bit just reading through it.

Have fun, it's a great little motor!
Clark Sr.

Rod Hawkins · Joined: 23 Dec 2012 Posts: 11

Rusty and Clark, thanks so much for the great info and quick replies. I belong and regularly visit several other forums (M3 forum, surfermag, and dirt bike forums) and have never had such complete answers to questions so quickly.

I just bought the Kart used, Margay 1.8 chasis (they don't seem to be all that popular) and the Leopard (older, non MY09) engine. My brother bought a couple Used Arrow chasis and the track/shop threw in brand new RPD motors for about the same price as my unit. When I finally got to the track, the track operator was very helpful (same guy my bro bought his stuff from) but he kept making comments about always being very careful since leapords as so well known the "grenade", "always have problems", "blow up", etc. It was a little discouraging and I was really starting to think I got the wrong motor. Then when he tells me I should get it completely rebuilt (top and bottom end, etc) about every 10 hrs (we don't compete, we just go out practice and have fun) and it will cost me $800 or more, along with other maintainance, I was really bummed (I am into dirt biking as well and was a wrench at a bike shop for several years, so I am definately not afraid to get my hands dirty). Way back I have worked on dirt bikes and my brother in law who just bought a kart as well, has experience doing top ends on 2t 125cc dirt bikes and says it should be pretty easy to do it on these as well. I just had no idea that you need a complete rebuilt at 10 hrs. So I am just trying to learn as much as I can.

That website is great and looks to have a ton of info. Very valuable!

I have a suspicion that the drum doesn't need to be replaced, since he just looked at the outside of it and said that. When I replace the sprockets and chain I will have to check it out and do more research. It is for sure not a MY09.

Is there some sort of scheduled maintenance guide for these motors so I know exactly what to do and when?

Also, my mychron was saying I was maxing out at about 16,600 rpm (current gearing is 10t and 76t) In reading this site, that sounds about right, but the link that was provided seems to state that for much longer engine life, I should stay under 15,000. Is that right? If so, I need to drastically change my gearing to more like an 11t and 76 or 75?). Would like to maximize the engine parts so I don't need to spend my life rebuilding this thing every other day.

Matt Dixon · Posted: Sun Dec 30, 2012 9:46 am Post subject:

Rod

Use a heat gun or torch to remove old drive gear and Red locktight to install new gear.

Keeping the RPMs in the low/mid 16's will extend the rebuild time. The guys that twist them to the high 17's need to keep fresh. Plus running a little rich will also keep you on track longer.

You can buy cheaper (non IAME) non legal gears since you just run for fun. By and extra for the toolbox because as stated they wear out.
_________________
Matt Dixon
94y Energy Corse/Swedetech

Dan Haynes · Posted: Sun Dec 30, 2012 9:46 am Post subject:

For higher levels of competition 10 hours is about right, but that is also true of the PRD. A full rebuild is about $1000 but they do not 'grenade' like he says. We have been running Leopards for about 4 years and never have grenaded one. We have had a few issues but most were mechanic related Embarassed

. The biggest problems with them are the starters. Second to that would be clutch assembly. My biggest piece of advice I can ever give anyone when it comes to maintaining a Leopard is to have an experienced Leopard guy remove and install your clutch the first time and watch him. Pay him if you have to. It will be money well spent. I have ruined 2 crank halves from improperly installed clutches. After learning the proper way I haven't had a problem with it.
_________________
Blaise Haynes
#3 Arrow X1-CIK
TaG
Cook Racing Engines Parilla Leopard

Oscar Biondi · Posted: Sun Dec 30, 2012 9:48 am Post subject:

Sounds like that guy is trying to sell you something. A full rebuild on a Leopard will cost you closer to $1,200-$1,500 but for recreational use you can get up to 40 hours out of your motor. 16,000 rpm will make it very happy and last a long time between rebuilds. Try a 74 rear sprocket and keep your 10t driver or use an 11t with an 82 or 81 rear.
If your sprockets are worn make sure you also replace the chain. A worn out chain will eat the sprockets fast.
The only specialty tool you need to replace the clutch is the clutch puller. The drum can be removed using a phillips screwdriver to hold the flywheel in place while you remove the 17mm nut.

Oscar Biondi · Posted: Sun Dec 30, 2012 9:49 am Post subject:

Clark Gaynor · Posted: Sun Dec 30, 2012 9:57 am Post subject:

Rob, we road race Leopards so we don't turn them much over about 14,000. I understand sprint folks turn them to about 16-16.5. But in road racing, they are over 12.5-13.5K for a LONG time!!! They are getting worked hard, but not spinning too much--if you understand what I mean.

We get ours Leopards done every two seasons, or about 15-20 hours. At that point we do the whole deal, top and bottom ends. And according to our engine builder, Brian Fisher, they look fine with that amount of time on them. I would suspect turning them over 16K, 15 hours would be about the max. But that's only a guess. Sprinters would know better---folks?

On the rebuilds, they take the crank apart and replace the rod and big end bearings. I personally wouldn't do it myself, but I know folks who do. It's very important the crank be pressed back together properly!!! Also, they DON'T have Nicasil(?) liners like bike motors, they're case iron. So when you replace a piston/ring, it has to be fitted properly.

$800 seems reasonable for a total rebuild, which would include top and bottom end, carb setup, reeds if needed, gaskets, etc.

I think the Leopard if a great, simple, fun, easy to tune and maintain motor. But again, that's just my opinion, others may argue otherwise.

Their weak link is their starter!!! Get an external starter when you get a chance, and be done with it. And for road racing, the clutch. But for your application, the clutch should be fine. (after you go over it!!!)

By the way, if you don't know how much time is on the motor---DON'T wait until the bottom end bearings take a S--T to have it rebuilt!!! That gets very costly!!! To say the least!

Have fun with it,
Clark Sr.

Dan Haynes · Posted: Sun Dec 30, 2012 11:22 am Post subject:

For sprint racing about 16,200-16,600 is the norm. FWIW-we have only had 2 starter failures in 4 years and we almost always use the key starter.
_________________
Blaise Haynes
#3 Arrow X1-CIK
TaG
Cook Racing Engines Parilla Leopard

Mike Lyda · Posted: Sun Dec 30, 2012 11:22 am Post subject:

Scott Heavin · Posted: Sun Dec 30, 2012 11:39 am Post subject:

When he said that the drum needed to be replaced, I'm guessing he meant the drive gear. I've run a drum for probably 200 hours without replacing it. Loctite it & let it dry good. Bad things happen when those 3 screws come lose.

As someone mentioned, when you changes sprockets, change your chain, too. Best advice I can give to someone new to TaG is to get an RK O-ring chain. It will take about half your frustration out of running a leopard. Yes, they're more, but once you get it aligned and tensioned right, you'll never have to adjust it again. A std. chain you'll have to mess with at least every hour of run time - if not more. My first year I went through probably 10 sprockets / chains / drive gears. Part of it was not paying attention and part of it was being a newbie driver - they're a lot harder on chains.

And as Dan said, find someone to walk you through everything the first time or two. Breaking something on one of these can lead to a $1200-$1600 rebuild. I had a guy help me a lot during the first year and still managed to screw up a lot. And that goes back to what I've said since my first year in karting - shops / tracks should teach classes in the off season.
_________________
Spec TaG Masters @ NCMP / #23

Dan Haynes · Posted: Sun Dec 30, 2012 1:32 pm Post subject:

Removal isn't that tricky but assembly must be done carefully. Any time you put a new/different friction hub on a crank you MUST lap it very good. Make sure the taper looks uniform all the way around. The next big thing is making sure your screw holes in the drum are clean of any dirt or grease. I use brake cleaner with q-tips to clean it then use red loc-tite to assemble it. Make sure to use the proper torque specs on everything. I use a DeWalt impact to install the friction hub on the crank. I tried a few times with a torque wrench and had some trouble with it coming loose. This has caused me to shear 2 keys and the hub spin on the crank. I have also had the drum screws back out and snap. This has ruined a few drums because of the bit drifting into the threads when trying to drill them out.

Since ensuring my lapping is very good and using an impact and cleaning the drum screw holes and loc-titing, I haven't had any problems.

Just make sure to get help the first time.
_________________
Blaise Haynes
#3 Arrow X1-CIK
TaG
Cook Racing Engines Parilla Leopard

Russell Stevens · Joined: 15 Oct 2012 Posts: 100

If you have to replace the front sprocket anyway go with the 11t. Also if you aren't min/maxing the kart get an O-ring chain. Creates a little more drag (robs HP) but lasts a lot longer.
Good luck and have fun.
Rusty

Jim Russell, Jr. · Advertiser Joined: 03 Oct 2001 Posts: 1535